NANTUCKET, United States, Nov 24, 2023 (BSS/AFP) - Joe Biden may have dipped in the polls recently but the 81-year-old US president wasn't afraid to take the plunge with his family Thursday on their annual Thanksgiving holiday trip.

Biden's granddaughter Naomi posted a photo of the president and the rest of the clan with striped towels standing on the beach on posh Nantucket island, off Massachusetts.

"Annual Biden fam polar bear plunge Happy Thanksgiving!" Naomi Biden wrote on X, formerly Twitter.

Her father Hunter Biden -- who is at the center of an impeachment inquiry against the president and separately facing gun charges -- was also in the photo, holding his youngest son Beau.

The White House confirmed that President Biden, who turned 81 on Monday, had taken part in the chilly family swim.

Democrat Biden has been coming to Nantucket for the Thanksgiving holiday with his family almost every year since the 1970s, but is likely to be needing a holiday more than ever this year.

A slew of recent polls show him trailing hard-right Republican rival Donald Trump in a likely November 2024 election rematch, with voters particularly concerned about Biden's age.

An NBC News poll released Sunday found Trump leading Biden 46 percent to 44 percent among registered voters, while a Yahoo News/YouGov poll released this week found Trump leading Biden 44 percent to 42 percent.

Biden has been playing on his image as a healer after he beat the divisive populist Trump in 2020, and he called for national unity in his Thanksgiving message this year.

"Stop the rancor," Biden said as he and wife Jill Biden phoned in live to television coverage of the annual Macy's department store Thanksgiving parade in New York.

"We have to bring the nation together, we have to treat each other with a little bit of decency."

- 'Fingers crossed' -

Meanwhile Biden is grappling with wars engulfing two key allies -- Israel and Ukraine --and has spent part of his time in Nantucket speaking to Middle Eastern leaders over the Gaza truce and hostage release due to start Friday.

"I'm not prepared to give an update until it's done," Biden told reporters as he and the first lady delivered pumpkin pies to Nantucket firefighters on Thursday.

Wearing a blue baseball cap, Biden said he was "keeping my fingers crossed" that kidnapped American toddler Abigail Mor Idan would be in the first batch of hostages to be released.

Biden's motorcade then returned along a bumpy dirt lane to the exclusive beachfront house of billionaire family friend David Rubenstein, where the president is spending this year's Thanksgiving as in previous years.

Nantucket, a former whaling town turned playground for the rich, has long been something of a refuge for Biden where he can gather his forces for upcoming battles while enjoying treasured family rituals.

The family started coming in 1975, when then-senator Biden was a widower with sons Hunter and Beau after the death of his wife and infant daughter in a car crash two years earlier.

He and Jill, who had recently started seeing each other, decided on Nantucket to avoid having to decide between their families for Thanksgiving, he wrote in his 2017 autobiography "Promise Me, Dad."

The memoir opens with a description of the last Thanksgiving Biden spent in Nantucket with his eldest son Beau, in 2014, seven months before Beau died of brain cancer at the age of 46.

Last year it was the scene for the first in a series of Biden family discussions on whether he should run for a second term, reportedly in the face of opposition from the influential first lady.

Now this Thanksgiving is the last before a brutal year of campaigning -- and an expected rematch with Trump.